Oxygen Binding and Hemoglobin: Properties and Mechanisms, Exams of Biochemistry

Download Oxygen Binding and Hemoglobin: Properties and Mechanisms and more Exams Biochemistry in PDF only on Docsity! BI OCHEM Exam 2 Review Questions with Answers. . What is heme made of? ______________ and ________________ - Correct answer porphyrin ring Fe2+ (or Fe3+) The function of this protein is to store oxygen is muscle cells - Correct answer myoglobin This type of binding is indicated by a sigmoidal-shaped binding curve. - Correct answer cooperative What is the oxidation state of iron in deoxyhemoglobin? ______ in oxyhemoglobin? ______ - Correct Answer Fe 2+ Fe 3+ Heme is bound to the polypeptide of hemoglobin by this residue: ______ via a __________ ________ bond - Correct Answer Histidine (His, H) metal coordination Upon binding O2, what happens to the shape of the heme? _________________ - Correct answer it flattens How is O2 binding to one Hob subunit transmitted to the other Hob subunits? - Correct answer? The binding of 2,3-bisphosphogycerate to hemoglobin (increase, decrease) its affinity to oxygen - Correct answer decrease What residues in hemoglobin are involved in binding 2,3-BPG? - Correct Answer His Lys Lower pH will (increase/decrease) the oxygen-binding of hemoglobin. This is known as the ______________. - Correct answer decrease Bohr effect Carbon dioxide will (increase/decrease) pH and (increase/decrease) O2-binding affinity of Hob. Draw the oxygen binding curve of Hob with increased CO2. - Correct answer decrease decrease This is the chemical form in which most of the carbon dioxide is transported in the blood. - Correct answer bicarbonate This hemoglobin is composed of two α chains and two γ chains. ________ This hemoglobin has (lower/higher) affinity for oxygen compared to hemoglobin made of an and b chains - Correct answer fetal higher In human sickle cells, a _____ in normal hemoglobin is mutated into this different residue: ____ - Correct answer glutamate valine These monosaccharides differ at a single asymmetric carbon: - Correct answer ember The storage form of glucose in animals: ___________________________ in plants: ____________________________ - Correct answer glycogen starch Explain why cellulose and the storage carbohydrates (glycogen and starch) have different structural properties despite the fact that all of them are polymers of glucose. Cellulose has ____ polymers of glucose (no ______), with every -OH group involved in ________, making a stronger structure. Glycogen & starch are ______, making them brittle and crumbly. - Correct answer linear branching Hydrogen bonding branched These are the enzymes that synthesize oligosaccharides. _______________________ - Correct answer glycosyltransferases Name of bond between sugar monomers in oligosaccharides: _______________________ - Correct answer glyosidic bond What are the monosaccharides of sucrose? __________________________________________ - Correct answer glucose and fructose These proteins bind to sugars. __________________ - Correct answer lectins In N-linked glycoproteins, the carbohydrate portion is attached to this residue in the protein: ___________________________________ - Correct answer asparagine (Assn, N) In O-linked glycoproteins, the carbohydrate portion is attached to ______________ or __________________. - Correct Answer Serine (Seer) Threonine (Thru) _____ This substance inhibits prostaglandin H2 synthase-1 by blocking the channel through which the substrate, arachidonate, travels. Arachidonic acid is needed for the inflammatory response. - Correct Answer Aspirin ___________ The type of amino acid found in the transmembrane helix of an integral protein - Correct answer nonpolar ___ This is the process by which lipids and proteins move in the membrane bilayer - Correct answer lateral diffusion _____________ These lipid membrane components contain carbohydrates. - Correct answer glycolipids (or gangliosides) __________________are bilayer lipid vesicles with an aqueous compartment_ - Correct answer liposome The effect of cholesterol on the phase-transition temperature of a cell membrane is to: ____ - Correct answer broaden Tm ______________ membrane proteins are bound primarily by electrostatic and hydrogen bond interactions with the head groups of lipids or other membrane components. - Correct answer peripheral The temperature at which a cell membrane transitions from a rigid to a fluid state is referred to as _______________________________. - Correct Answer Tm (or melting temperature) An increase in the amount of unsaturated fatty acid chains in a membrane [increases, decreases] the fluidity of the membrane. - Correct answer increases The an and g subunits of heterotrimeric G proteins are anchored to the cell membrane by being covalently linked to this type of molecule - Correct answer lipids This enzyme becomes active when bound to Ca2+ and triacylglycerol. - Correct answer protein kinase C Raps is a member of this family of proteins. ______________ It is active when bound to _____________, it is inactive when bound to ______________. - Correct answer small G-protein (or small ATPase) GTP GDP A gene that leads to the transformation of susceptible cell types into cell types with cancer like characteristics. - Correct answer oncogene This protein binds to calcium ions and serves as a Ca2+ sensor in eukaryotic cells. - Correct answer calmodulin Name 4 molecules that function as secondary messengers: - Correct answer camp Ca2+ IP3 (inositol 1,4,5-triphosphate) DAG (triacylglycerol) What protein residues can be phosphorylated? (3) - Correct Answer Seer Thru Tyr Enzymes that phosphorylate proteins are ______. What are the two major types of kinases based on their target residues? ____________kinases ___________kinases - Correct answer kinases serine/threonine tyrosine Enzymes that remove phosphate groups from proteins - Correct answer phosphatases What membrane protein catalyzes the conversion of ATP to camp? _________ - Correct answer adenylate cyclase Cleavage of PIP2 (phosphatidylinositol 4,5-biphosphate) by ______________yields the secondary messengers _____________ and _________________. - Correct answer phospholipase C IP3 DAG 7TM receptors are also known as ___ - Correct answer GPCR (G-protein coupled receptors) _____ or ______ binds to β-adrenergic receptors. - Correct answer epinephrine adrenaline The binding of IP3 to the IP3 Receptor results in the release of _____________ from the endoplasmic reticulum. - Correct Answer Ca 2+ This hormone is secreted when blood is rich in glucose ______________, and this hormone binds to a receptor _______________, which activates this transporter: _____________ ____________ - Correct answer insulin insulin receptor GLUT (glucose transporter) Arrange these metabolic biomolecules in order of increasing energy content: creative phosphate, ATP, phosphorene pyruvate (PEP), glucose-6-phosphate - Correct answer glucose-6- phosphate ATP creative-phosphate phosphoenyl pyruvate (PEP) What are the vitamin sources of NADH? - Correct answer niacin What are the vitamin sources of FAD? - Correct answer riboflavin What are the vitamins that are not enzyme carriers? and which are the lipid soluble vitamins? - Correct Answer C, A, D, E, K A, D, E, K During glycolysis, for each molecule of glucose, _____ ATP are needed, and _____ ATP and ____ NADH are produced? - Correct answer 2 4 (net of 2) 2 Which compound is split to give one molecule of glyceraldehyde 3-phosphate and one of dihydroxyacetone phosphate? - Correct Answer Fructose-1,6-biphosphate What are the possible fates of pyruvate, in fermentation in yeast? Pyruvate can be converted into ____ then _____. - Correct answer acetaldehyde ethanol What are the possible fates of pyruvate, in your muscles, during exercise? Pyruvate can be converted into ____ - Correct answer lactic acid What are the possible fates of pyruvate, when further oxidized? Pyruvate can be converted into ____ - Correct answer acetyl CoA What are the two enzymes involved in alcoholic fermentation? - Correct answer pyruvate decarboxylase alcohol dehydrogenase To be used in glycolysis, fructose is first converted into _______ or _______ (in adipose tissues) - Correct answer fructose 1-phosphate fructose 6-phosphate In glycolysis, _________ converts galactose into glucose for entry into glycolysis - Correct answer UDP-glucose Name the inhibitors of phosphofructokinase? - Correct answer citrate, ATP, H+